London Power’s QS-HV Quiet Power Supply for High-voltage Tube Amps provides a significant reduction of supply-borne noise and hum – typically 60dB from 50Hz to 120Hz. Supply noise is especially problematic for single-ended amps, but the QS-HV will make an SE amp as quiet as a well-balanced push-pull amp. Quiet anything from a Champ, Valve Jr., GA-3/4/5/6 and all the clones, to “big” SE amps using 845s or 211s at 800V, to all those 500V push-pull amps, including Marshall, Fender, Peavey, Hiwatt, Mesa, and nearly every other amp brand and model.
Note that most single-ended amps for guitar operate at less than 450V and/or have limited space in their chassis. See our QS-LV for these amps.
Push-pull amps benefit from QS-HV’s hum reduction, too. Switching to triode mode in most amps causes an increase in hum. With QS-HV installed the supply will be QUIET and so will both triode and pentode operating modes. Tame the noise of your clipped plexi, Trainwreck, Komet, Marshall or other non-master-volume amp.
Supply voltages up to 900Vdc are accommodated. On-board current limiting protects both QS-HV and your amp. In most very high-power tube amps, quieting the supply from the screen node onward achieves good effect.
Proper heat sinking is required. In most amps, the chassis will suffice as the heat sink. In amps over 100W, or that are cathode biased for 30W and over, it is best to add a fan to cool the chassis. An aluminum heat sink is also a good idea on larger amps.
Installation of QS-HV will bring your amp one step closer to achieving the noise performance of London Power’s amp line.
PCB dimensions: 2,7 x 1.7″, 69 x 43mm
Kit requires assembly.
Kit includes notes with installation tips + layout and schematic diagrams of the kit.